1. Field of the Invention
This invention relates to a novel polysaccharide RBS substance and antitumor agent containing said substance as the effective component.
2. Description of the Prior Art
As is known in the art, polysaccharides are obtained from various sources, for example, Basidiomycetes (Japanese Patent Kokai Koho No. 94012/1978), bacteria (Japanese Patent Kokai Koho No. 76896/1979), mould (Japanese Patent Publication No. 59097/1978), algae (Janese Patent Kokai Koho No. 28923/1977), and grains (Japanese Patent Kokai Koho No. 139713/1978).
It is also known that these polysaccharides have antitumor activity. However, various problems, for example, low yields, complicated production process, toxicity, etc., are encountered in using such polysaccharides as an antitumor agent.